פרסומים

This review deals with the role of nerve growth factor (NGF) in healing process as a result of injury. The role of both trkA(NGFR) and p75(NTR) specific NGF receptors and their contribution in the complex network of tissue repair process, is discussed and highlighted in view of recent findings. In fact, NGF represents a significant advance in the treatment of etiologically different ulcers (corneal ulcers, pressure ulcers, post-viral infections, chemical burns) and might shorten the recovery process. For these diseases, no specific treatment is actually available. It is reasonable that apart from NGF and/or neurotrophins a different time-course of trkA(NGRF)/p75(NTR) expression, might regulate the final process. In summary, these novel findings on the potential pro-healing capacity of NGF might open new possibilities for this growth factor in modulating the healing processes in several pathological conditions.

The aim of the study was to isolate and characterize a population of neuronal progenitors in the human umbilical cord blood (HUCB) mononuclear cell (MNC) fraction, for in vitro manipulation towards neuronal differentiation. Selection of the HUCB neuronal progenitors (HUCBNPs) was based on the neuronal prerequisite for adherence to collagen. Populations of collagen-adherent, nestin-positive (94.8+/-2.9%) progenitors expressing alpha1/2 integrin receptors, as revealed by Western blot and adhesion assay using selective antagonists, were isolated and survived for more than 14 days. In vitro differentiation of the HUCBNPs was achieved by treatment with 10% human SH-SY5Y neuroblastoma cell-conditioning media (CM) supplemented with 10 ng/ml nerve growth factor (NGF). Some 83+/-8.2% of the surviving progenitors acquired a neuronal-like morphology, expressed by cellular outgrowths of different lengths. About 35+/-6% of the HUCBNPs had long outgrowths with a length/cell diameter ratio greater than 2, typical of developing neurons. The majority of these progenitors, analyzed by immunocytochemistry and/or RT-PCR, expressed common neuronal markers such as microtubule-associated protein 2 (MAP-2; 98.5+/-2%), neurotrophin receptor (TrkA; 98.5+/-0.06%), neurofillament-160 (NF-160; 94.2+/-1%), beta-tubulin III (89.8+/-4.2%) and neuron specific enolase (NSE). Combined CM and NGF treatment induced constitutive activation of the mitogen-activated protein kinases ERK2 (36-fold vs control), p38alpha (nine-fold vs control) and p38beta (23-fold vs control), most likely related to survival and/or differentiation. The results point to operationally defined conditions for activating neuronal differentiation of HUCBNPs ex vivo and emphasize the crucial role of neuronal CM and NGF in this process.

We describe a new method for the prepn. of org. nanoparticles from nanoemulsions which were prepd. by the phase inversion temp. (PIT) method. This is a low-energy technique which does not require any special equipment such as high pressure homogenizers. In this work, the method is demonstrated for prepn. of nanoparticles of poly-lauryl acrylate contg., in some cases, a crosslinker (trimethylolpropane triacrylate-TMPTA) and pyrene as microviscosity and micropolarity probes, resp. The nanoemulsions were prepd. by using a poly(oxyethylene) nonionic surfactant, Brij 96V (POE (10) oleyl alc.), and combinations of Brij 96V and Brij 92V (POE (2) oleyl alc.), with acrylate monomers which form the oil phase in the oil-in-water (O/W) emulsions. The nanodroplets were polymd., yielding nanoparticles having an av. diam. between 50 and 120 nm with a narrow size distribution, using a water-sol. thermal initiator (ammonium persulfate) and activated by ferrous ions, Fe+2. The emission colors of the pyrene-embedded nanoemulsions changed from blue to violet after polymn., due to the absence of excimers. This method may be applied for the prepn. of a variety of polymeric nanoparticles, in which functional mols. are embedded within the particles. [on SciFinder(R)]

Aminoglycosides can readthrough premature termination codons (PTCs), permitting translation of full-length proteins. Previously we have found variable efficiency of readthrough in response to the aminoglycoside gentamicin among cystic fibrosis (CF) patients, all carrying the W1282X nonsense mutation. Here we demonstrate that there are patients in whom the level of CF transmembrane conductance regulator (CFTR) nonsense transcripts is markedly reduced, while in others it is significantly higher. Response to gentamicin was found only in patients with the higher level. We further investigated the possibility that the nonsense-mediated mRNA decay (NMD) might vary among cells and hence governs the level of nonsense transcripts available for readthrough. Our results demonstrate differences in NMD efficiency of CFTR transcripts carrying the W1282X mutation among different epithelial cell lines derived from the same tissue. Variability was also found for 5 physiologic NMD substrates, RPL3, SC35 1.6 kb, SC35 1.7 kb, ASNS, and CARS. Importantly, our results demonstrate the existence of cells in which NMD of all transcripts was efficient and others in which the NMD was less efficient. Downregulation of NMD in cells carrying the W1282X mutation increased the level of CFTR nonsense transcripts and enhanced the CFTR chloride channel activity in response to gentamicin. Together our results suggest that the efficiency of NMD might vary and hence have an important role in governing the response to treatments aiming to promote readthrough of PTCs in many genetic diseases.

Nanoparticles having reactive pyrrole residues were prepd. from poly(1-ethoxyethyl glycidyl ether)-block-poly(L,L-lactide) block copolymer. The nanoparticles were electropolymd. in aq. media through the oxidn. of the pyrrole residue and in the presence of pyrrole to form a nanocomposite thin film. The novel synthesis of these pyrrole-functionalized nanoparticles is described and the electrochem. deposition of the corresponding coating is characterized using electrochem., SEM and EDX. [on SciFinder(R)]

We identify a highly specific mutation (jf18) in the Caenorhabditis elegans nuclear envelope protein matefin MTF-1/SUN-1 that provides direct evidence for active involvement of the nuclear envelope in homologous chromosome pairing in C. elegans meiosis. The reorganization of chromatin in early meiosis is disrupted in mtf-1/sun-1(jf18) gonads, concomitant with the absence of presynaptic homolog alignment. Synapsis is established precociously and nonhomologously. Wild-type leptotene/zygotene nuclei show patch-like aggregations of the ZYG-12 protein, which fail to develop in mtf-1/sun-1(jf18) mutants. These patches remarkably colocalize with a component of the cis-acting chromosomal pairing center (HIM-8) rather than the centrosome. Our data on this mtf-1/sun-1 allele challenge the previously postulated role of the centrosome/spindle organizing center in chromosome pairing, and clearly support a role for MTF-1/SUN-1 in meiotic chromosome reorganization and in homolog recognition, possibly by mediating local aggregation of the ZYG-12 protein in meiotic nuclei.

Protein/polysaccharide conjugates were used to stabilize oil-in-water (O/W) emulsions and oil-in-water-in-oil (O/W/O) double emulsions. By properly selecting the type of protein (WPI) and the polysaccharide (xanthan gum, fenugreek gum), and by using specific ratios of the two biopolymers and their soln. concns., amphiphilic biopolymer adducts were formed. A synergism in the emulsification properties was obsd. in WPI/polysaccharide conjugates compared to each of the biopolymers alone. Submicron droplets of oil-in-water were obtained by applying a high-pressure homogenization process during the first step of the double emulsion prepn. It was also demonstrated that double-emulsion globules could be formed with a very high yield of addendum entrapment (above 95%) during the second step of the emulsification process. The differentiation between the two types of oils, O1 (the inner) and O2 (the outer), in the double emulsions enabled high entrapment capacity of the addendum in the inner oil phase. In addn., when the inner oil phase (O1) was a 1:1 (wt./wt.) mixt. of MCT/triacetin and the external oil phase (O2) was a silicone oil, it was possible to slow the release of the entrapped matter while the soly. of the inner phase in the external oil phase remained const. The addendum soly. in the external oil phase was not a limiting factor in the release process. The presence of hydrophobic additives (i.e., 1% glycerol monooleate) in the inner oil phase helped to better control the transport to the external oil phase. In the best case, the addendum leakage to the external oil phase was only ∼0.2% during a period of 28 days at 25°. WPI/xanthan gum adducts served as thick and efficient barriers against release of flumethrin (a veterinary drug model) entrapped in the core of the O/W/O multiple globules. [on SciFinder(R)]

We define the riskiness of a gamble g as that unique number R(g) such that no-bankruptcy is guaranteed if and only if one never accepts gambles whose riskiness exceeds the current wealth.